1. Field of the Invention
The present invention relates to an improvement of a motorized roller incorporating a motor in a roller body and further to a motor unit constituting such a motorized roller.
2. Description of the Related Art
A motorized roller is known as a component of a roller conveyor. A motorized roller, as disclosed in a patent document 1, incorporates a motor and a reducer in a roller body. Driving of the motor rotates the roller body.
FIG. 24 is a cross section of a motorized roller disclosed in the patent document 1.
A motorized roller 100 in the art includes a roller body 101 penetrated is by a fixed shaft 110. The roller body 101 has both ends each provided with a lid 102, and the shaft 110 has both ends 105 and 106 protruding out of the lids 102 respectively. The end 105 is of a hollow shape with an electric cable 107 inserted therein. Power is fed to a motor 103 incorporated in the body 101 via the electric cable 107.
There is also another configuration having a connector 111 provided at a distal end of the electric cable 107 so as to simplify electric wiring. The above-mentioned patent document 1 discloses such a configuration in which the connector 111 is provided at the distal end of the electric cable 107.
Though the connector 111 is provided at the distal end of the electric cable 107 in the patent document 1, patent documents 2 and 3 each discloses a modified motorized roller having still another configuration in which the above-mentioned connector is incorporated in the fixed shaft. According to the configuration disclosed in the patent documents 2 and 3, the connector is housed in a hollow part of the fixed shaft of the motorized roller and a separately prepared connector is connected to the fixed shaft so as to feed power and/or to send and receive signals.
Such a configuration in which a connector is housed in the fixed shaft is disclosed in more detail in a patent document 4.
Specifically, the motorized roller as defined in claim 1 in the patent document 4 is a motorized pulley or roller including a stationary roller shaft, a generally cylindrical drum mounted on the roller shaft for rotation around the axis of roller shaft, an electric drive assembly mounted on the roller shaft and disposed inside the cylindrical drum from rotating the drum about the roller shaft, a recess formed in one end of the roller shaft, a first electrical connector disposed in the recess in the end of the roller shaft and electrically connected to the electric drive assembly, and a second electrical connector operatively connected to a power source and shaped to mate with said first connector to provide power to said electric drive assembly when the first and second connectors are mated.
FIG. 25 is a cross section of the motorized roller disclosed in the patent document 4.
The motorized roller disclosed in the patent document 4 mainly consists of a roller body 120 penetrated by a fixed shaft 121 and a motor 122 functioning as an electric drive assembly and mounted on the shaft 121.
More specifically, in the motorized roller disclosed in the patent document 4, the fixed shaft 121 penetrates through the roller body 120. Further, a rotor 123 of the motor 122 is attached to and a stator 125 of the motor 122 is fixed to the fixed shaft 121.
In this way, in such the motorized roller as disclosed in the patent document 4, all members of the motor 122 functioning as the electric drive assembly are located around the shaft 121, so that “an electric drive assembly mounted on the roller shaft and disposed inside the cylindrical drum from rotating the drum about the roller shaft”, which the claim recites, is realized.
Patent documents 5 and 6 each disclose a motor unit, which is combined with a roller body so as to constitute a motorized roller.
The motor unit disclosed in the patent documents 5 and 6 is an integral piece of a motor and a reducer, being inserted into a separately-prepared roller body so as to produce a motorized roller having a discretionary length. The motor unit mainly consists of a cylindrical casing having one end from which a short shaft protrudes and the other end provided with an output member.
The motor unit has the cylindrical casing with the short shaft integrally fixed to the one end of the casing. In the motor unit disclosed in the patent documents 5 and 6, the short shaft is a very short shaft and only fixed integrally to the casing, having an end at an open end of the casing. Therefore, the short shaft does not penetrate through the casing, not existing in the casing. In a hollow space within the casing, the motor and the reducer is incorporated. The reducer has an output shaft protruding from the other end of the casing and having the output member.
The motor unit disclosed in the patent documents 5 and 6 is inserted into the separate-prepared roller body so as to engage the output member with an inner face of the roller body.
The short shaft of the motor unit is supported at an open end of the roller body via a shaft bearing with a distal end of the shaft protruding from the roller body so as to serve as a fixed shaft at one end of the motorized roller.
Another short shaft is attached rotatably to the other end of the roller body, serving as a fixed shaft at the other end of the motorized roller.
In the motorized roller employing the motor unit in the patent documents 5 and 6, the fixed shaft does not penetrate through the roller body. The fixed shafts at the both ends of the motorized roller are short and only fixed to the both ends of the roller body.
More specifically, one of the shafts supports only the one end of the roller body and the one end of the casing of the motor unit. The other of the shafts supports only the other end of the roller body. Herein, in this motorized roller, an electric driving part is not held on the roller shaft, not meeting a condition in the patent document 4.
A patent document 7 discloses such a conveyor that the conveyor is divided into a plurality of zones, each of which has a sensor for detecting presence of an article to be conveyed, so that the conveyor drives a motorized roller under such a condition that an article exists in one zone and no article exists in a zone ahead of said zone. According to the conveyor disclosed in the patent document 7, the motorized roller is driven only when necessary. Therefore, the conveyor disclosed in the patent document 7 repeatedly makes the motorized roller start and stop at frequent intervals.    Patent Document 1: JP 2004-18184 A    Patent Document 2: JP 63-133515 U1    Patent Document 3: JP 63-133516 U1    Patent Document 4: U.S. Pat. No. 5,442,248 A    Patent Document 5: JP 2002-145438 A    Patent Document 6: U.S. Pat. No. 6,672,449 B2    Patent Document 7: JP 2005-67811 A